(also known as a sinus infection) is a medical term used to describe inflammation (swelling and irritation) of the paranasal sinuses. Because many cases of sinusitis are caused by an infection, you may hear the terms "sinus infection" and "sinusitis" used interchangeably.
What Are the Paranasal Sinuses?
The paranasal sinuses are hollow air spaces located within the skull. They include the frontal, maxillary, ethmoid, and sphenoid sinuses. These sinuses connect to the nasal passages through an opening that allows movement of air and mucus in between the nose and sinuses.
Types of Sinus Infections
There are two main types of sinus infections: acute and chronic. An acute sinus infection is diagnosed when symptoms have lasted no longer than four weeks. A chronic sinus infection
is diagnosed when symptoms have lasted for at least 12 weeks, despite medical treatment. Sinus infections may also be classified as subacute or recurrent.